Salinity levels vary spatially in coastal areas, depending on proximity to freshwater sources, and may also be slowly decreasing
as a result of anthropogenic climatic changes. The impact of salinity on host–parasite interactions is potentially a key regulator
of transmission processes in intertidal areas, where trematodes are extremely common parasites of invertebrates and vertebrates.
We investigated experimentally the effects of long-term exposure to decreased salinity levels on output of infective stages
(cercariae) and their transmission success in the trematode Philophthalmus sp. This parasite uses the snail Zeacumantus subcarinatus as intermediate host, in which it asexually produces cercariae. After leaving the snail, cercariae encyst externally on hard
substrates to await accidental ingestion by shorebirds, which serve as definitive hosts. We found that at reduced salinities
(25 or 30 psu), the cercarial output of the parasite was lower, the time taken by cercariae to encyst was longer, fewer cercariae
successfully encysted and encysted parasites had lower long-term survival than at normal seawater salinity (35 psu). The strong
effect of salinity on the replication and transmission of this parasite suggests that there may be sources and sinks of transmission
to birds along coastal areas, depending on local salinity conditions. Also, unless it evolves to adapt to changing conditions,
the predicted reduction in salinity as a consequence of climate change may have negative impact on the parasite’s abundance. 相似文献
Environmental Science and Pollution Research - Groundwater pollution seriously threatens water resource safety due to high-intensity land use throughout the world. However, the relationship between... 相似文献
Nanoplastics are widely distributed in freshwater environments, but few studies have addressed their effects on freshwater algae, especially on harmful algae. In this study, the effects of polystyrene (PS) nanoplastics on Microcystis aeruginosa (M. aeruginosa) growth, as well as microcystin (MC) production and release, were investigated over the whole growth period. The results show that PS nanoplastics caused a dose-dependent inhibitory effect on M. aeruginosa growth and a dose-dependent increase in the aggregation rate peaking at 60.16% and 46.34%, respectively, when the PS nanoplastic concentration was 100 mg/L. This caused significant growth of M. aeruginosa with a specific growth rate up to 0.41 d?1 (50 mg/L PS nanoplastics). After a brief period of rapid growth, the tested algal cells steadily grew. In addition, the increase in PS nanoplastics concentration promoted the production and release of MC. When the PS nanoplastic concentration was 100 mg/L, the content of the intracellular (intra-) and extracellular (extra-) MC increased to 199.1 and 166.5 μg/L, respectively, on day 26, which was 31.4% and 31.1% higher, respectively, than the control. Our results provide insights into the action mechanism of nanoplastics on harmful algae and the potential risks to freshwater environments.
Characterization of the typical petroleum pollutants, polycyclic aromatic hydrocarbons (PAHs) and n-alkanes, and indigenous microbial community structure and function in historically contaminated soil at petrol stations is critical. Five soil samples were collected from a petrol station in Beijing, China. The concentrations of 16 PAHs and 31 n-alkanes were measured by gas chromatography-mass spectrometry. The total concentrations of PAHs and n-alkanes ranged from 973 ± 55 to 2667 ± 183 μg/kg and 6.40 ± 0.38 to 8.65 ± 0.59 mg/kg (dry weight), respectively, which increased with depth. According to the observed molecular indices, PAHs and n-alkanes originated mostly from petroleum-related sources. The levels of ΣPAHs and the total toxic benzo[a]pyrene equivalent (ranging from 6.41 to 72.54 μg/kg) might exert adverse biological effects. Shotgun metagenomic sequencing was employed to investigate the indigenous microbial community structure and function. The results revealed that Proteobacteria and Actinobacteria were the most abundant phyla, and Nocardioides and Microbacterium were the important genera. Based on COG and KEGG annotations, the highly abundant functional classes were identified, and these functions were involved in allowing microorganisms to adapt to the pressure from contaminants. Five petroleum hydrocarbon degradation-related genes were annotated, revealing the distribution of degrading microorganisms. This work facilitates the understanding of the composition, source, and potential ecological impacts of residual PAHs and n-alkanes in historically contaminated soil.
Environmental Science and Pollution Research - The abatement of SO2 and the utilization of copper tailings are identified as two attention-attracting environmental issues in the copper smelter. In... 相似文献
Environmental Science and Pollution Research - Extensive attention has been paid to the treatment and disposal of dredged material, and there is a need to clarify the feasibility of recycling... 相似文献
